<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
function a(){
	var p = document.getElementById("tex");
	if(!p.value|| p.value=="请填写不通过原因"){
		p.value="";
		p.style.color='black';
	}
	
}
function b(){
	var p = document.getElementById("tex");
	if(!p.value){
		p.value="请填写不通过原因";
		p.style.color='gray';
	}
}
</script>
</head>
<body>
	<div style="width: 300px;height: 150px;">
		<div style="margin:0 auto;width:200px;">
		<textarea rows="10" cols="35" id="tex" style="color: gray;" onmousedown="a()" onblur="b()">请填写不通过原因</textarea>
		</div>
	</div>
</body>
</html>